Electric steam boiler



Allg. 30, 1932. S. N CQATES ELECTRIC STEAM BOILER 'Filed Aug. 1e, 1928 2 sheets-sheet 14 Filed Aug. 16, 1928 2 Sheets-Sheet .yczn @yN Coazes Patented Aug. 30, 1932 UNITED STATES SYDNEY N. COATES, F SEATTLE, WASHINGTON ELECTRIC STEAM BOILER Application led August 16, 1928. Serial No. 299,962.

My invention relates to an improvement in that type of small steam boilers which is designed to produce a considerable quantity l of steam for instant use, or a lesser quantity for continuous use. For example such a boiler may servethe purposes of a tailor in connection with a clothes pressing machine, where the boiler may be called upon frequently, but intermittently, for some little quantity of steam, or in a bakery, where the air is to be moistened during a period of some length. Y i

It is necessary in suchv boilers that means be provided for heating the water rapidly to a temperature suicient to make steam at the pressure desired, usually not in excess of'95`pounds per square inch, to the end that afsuicient quantity ofk steam of the desired temperature may be kept available. This, gq' then, isthe primary object of my invention ;-to produce a boiler having a small but suicient capacity, and the ability to produce steam rapidly. Alsoit is an object tov produce such a boiler, wherein electricity may be employed as the source of power, and

wherein the efficiency of the boiler ap-V preaches 100%.

It is a further object to provide a means in such a boiler whereby the electric heating element may quickly and easily be replaced When burned out, and installed in such a manner that it is not necessary to dismantle any portion ofthe boiler, and so` that the quantity of water in the boiler may a5 be kept at a minimum to permit its heating most rapidly. It is also an object so to in-V stall the electric heating elements that they will have the longest life, and be least subject to loss of efliciency and to burning out from the collection of scale.

Itis a further object to provide ya boiler of the type described, which is simple in its construction, and yet complete and sturdy enough for long continued service; in other Words, va boiler which combines simplicity and efiiciency. y

It is also an object to provide in such a boiler a means for utilizing the tendency to deposit scale as a means for better insulating the boiler, andl especially portions whichare not easily insulated otherwise, and to decrease the dead water space within the boiler.

Other objects will be ascertained from a study of the specification and drawings forml ing a part thereof.

My invention comprises the novel parts and the novel combination thereof, al1 as shown in the accompanying drawings, described in the speciiication, and particularly defined by the claims terminating the same. 6b

In the accompanying drawings I have shown my invention in a form which is now preferred by me, it being understood that other forms may be adopted, within the claims, and that the boiler may be made in o5 various capacities, and that its design will necessarily change somewhat with the-change in capacity. Y

Figure 1 is a general front elevation of my boiler. 1 7o Figure 2 is a general axial Section through the boiler.

Figure 3 is a transverse section through the boi-ler on the plane of the heating element. '(5V Figure 4 is an elevation of the casing through which the heating elements are inserted and in which are contained the electrical connections.

` Figure 5 is a detail section on an enlarged so scale of the construction and support of the lower end of the boiler casing.

'The boiler is preferably of the upright type, comprising a cylinder` 1 having dished heads 10 and 11, constructed according to the 85 requirements of the A. S. M. E. boiler code. This includes flanges 12 at the peripheries of` the two heads, by means of which the heads are welded or similarly secured to the cylindrical shell 1. Such an upright boiler provides a water space in its lower part, and as much of the upper portion as may be required forms the steam dome, or space from which the steam is withdrawn. Water is supplied through a valved connection 2, a T-itting 20, and a nipple 13, secured in the dished bottom head 11 of the shell and projecting slightly into the water space, the T- fitting 20, or a nipple secured thereto, beingl screwed within the nipple 13. 'A second con- 100 1 and by thus positioning these heating ele Y 5f)'nected withbinding rposts 61,'outside Yof the nection 21 to the T-iitting 2(l)vprovides'a l lvalved blow-off pipe, as is required by the boiler code.

Steam may be withdrawn through a valved connection 3, secured within a nipple 24 in the dished upperhead 10 of the boiler shell. The nipple 24 should extend as little within the shell'as is possible, so as to take off steam at approximately the highest point.`

To comply with code requirements, or forV the convenience of the operator, such 'devices Vas-the safety valve V4, the gage 40, the waterk glass 41, and the try-cocks 42, may beeinployed, and are suitably connected to the boiler shell 1, or to its heads 10 or 11, Vas may befsuitable,

i At .a Poi s ,hellas may be, feasible, nipples 5 are .secured -in apertures in the shell f1. `This point would ordinarily be at the upperrtermination .of

y the flanges12 of thebottom 171.V Theaxesjof thesenipples k,are substantially*horizontal,

and as many as maybe necessary are placed at the level-indicated'. fGf course, -it may not befeasible to place allthat maybe desired at thisylevel, and' consequentlyV others, 'as are indicatedat 50, may be placed above4 the nipples5,thefnipples 5 and 5() being identical Vexceptin location.k ;However, the nipples 5()V should not bei'placedy far above lthe nipples, and should` always be below therlevel of waterl to be maintained in the boiler. rlheheating elements, generally designated by the numeral `6,-are receivedin these nipplesf and 50,

ments as nearly as Ymaybe at the bottom of theY boilerithe amount vof dead Sptl'beQW' them is kept at a minimum, and the level of water need onlybe sutli'cienttorecoverV them. Thus, with the minimum quantity of water inthe boiler, thatA quantity can be' heated the more rapidly. Y

`The heating elements 6 maybe of any suit-l able form, but l prefer that they be made in the .torm of bent'tubes, as best'shown inYV Figure 3,'with the coiledresistance :wire en Y closed and insulatedl therein, these tubes being received in plugs 60, which will thread intoV the'nipples 50, andthe elements being con plugsGO. Y Y.

Y 4T here is an advantage inherentin positioning theheating elements horizontally, other thanthat of keeping a low water level, .asl J has lbeen explained. These heating elements are in directconta'ct withthe water, obviatf,V ing heating ashell or tube externally, and.

thus Vincreasing the efficiency of vthe boiler over those heated by a flame, or by induction,

but .this causes ebullition to occur at theele, ments themselves, and the deposition of scale Y* occursgat` thisgpoint, ythe Vhottest withinA the b ,oiler` i With an element vertically disposed, whetherwith'the.plug (iOjup. (which is practical)Y onwith .Y the plug "down, the(4 heatYAY tas near ofv the boiler will be most intense at the highest point of the element, and here will be the greatest ebullition, and the greatest Y formation of scale. Scale` will adhere to the tip of the element, if that be uppermost, and will progress downward and build up in thickness, and in a comparatively short time will so insulate the 1 element that it will fuse, or burn out.` With the element horizontal the intense heat is distributed over a far greater area, making the' average temperature lower, and such scale as collects is distributed more evenly; but most important of all, it will collect only upon `the upper side of the element, andthe lower side will always remain free from scale, and in intimate contact with the water. Ex-

by arco'ver plate 17, to completely surround the projecting ends of the elementsand to'V keep them inca de adair space. In addition,` the bottom of this box 16 maybe insulated by iilling in the chamber and the interstices' between the nipples 5'andv 50 with an insulat` Y ing cement, as is indicatedy at,V 62, whereby the shell is preventedfrom losing heat byradia` tion, l Vand to i a large extent, by conduction.' Theelectrical connections, as willbe under-V stood, 'areftaken off through asuitable apei'-A .turel connecting to an Voutlet box 18 (see Fig'-l ures 1and4). n

"Itis necessary that such `boilers as'this be constructed cheaply, yet Y that they |be, held together V.topejrmit the transportation of the boiler, 'and to make the boiler sturdy andV durable. Itis also necessary that the shellbe properly insulated, therefore I have shown acasing V7 in cylindrical form, surrounding.

the shellrl; fThis casingalso has a cover 70,I

which maybe fitted on lover the upper end of th Cylindrical casing 7to cover the top ofthe boiler, and the space between the casing 7 Vand the shell 1, and between the cover Y Y 70 and the top .10 of the boiler shell, may be filled in with insulation, as is indicated at 71 in Figure 2. This may conveniently be such material as rock wool, which forms a good in. sulation for such purposes as this. Y I 'l It willbe noted that it is necessaryk tocut out thecasing 7 to permit the passage'of the casing downwardly over the projecting box 16. VThe casing 7 may be'suitably apertured" to tit the box 16, and may then be'slitv as is indicated at 72, and the Vband 7 3 turned backV` warvdly, inwhich position thecasing 7 maybe iitted over the shell 1 and the Vbox 16, wherel upon thestripj73 Vmay be returned into the' cylindrical Shape beneath the bottom ofthej box 16, and secured by a strip 74, which may be riveted or otherwise secured in place, connected to the casing 7, as is best seen in Figure 1.

It is desirable that the boiler and its casing be supported above the floor, as otherwise there is a possibility of damage to woodwork. Also with the boiler elevated, it is possible to make and control the underneath connections, such as the water supply 2 and the blow-off 21. Therefore, I provide a platform or table 8, supported on legs 80, which may be secured thereto by some such means as the stove bolts or cap screws 81, and this table 8 is made of a diameter so that it will include the shell 1, but will fit just inside of the casing 7. The shell 1 Inlay be secured thereto by such means as the brackets 19 and bolts 82 (see Figure 2).

The boiler is manufactured by first assembling the shell and the casing 16 complete, and then supporting the same upon the table 8, securing the shell in place by the bracket-s 19 and bolts 82, as has been described. It will be noted that the end of the cylindrical shell 1 extends downwardly just suflicient to rest on the table 8, and to lie in at least the same plane, and not above the plane, of the lowermost point of the dished bottom 11. Thus the shell l bears the entire, or the major portion, of the Weight of the boiler supported upon the table 8. A pad 83 of insulation may be coextensive with the plate 8. The casing 7 is now slipped into place, and it will rest temporarily upon projecting corners 84 of the legs 8, as is seen in Figure 5. This supports the casing 7 in position relative to the boiler shell 1, for the casing extends outside of the plate 8, as will be seen in igure 5, and while in this condition the insulation 71 may be put into place.

Now the various fittings are secured through the casing 7 into the shelll and its ends, and after these are in place it will be evident that the casing cannot be displaced. The boiler thus is in condition for handling.

The heating elements, all being maintained low in the shell, will need but a slight amount of water, as proportioned to the entire capacity of the boiler shell, and this small capacity of water is quickly heated. Also, it will be notedthat 'the nipple 13 in the bottom 11 extends upwardly somewhat, and as all space below the lowermost heating element 6 is dead space, the nipple 13 may extend well upwardly towards this lowermost heating element. In this position, it forms a dead space around it in the dished portion of the bottom, which, in a short time, fills with scale. This scale forms an excellent insulating material, and assists in preventing loss of heat through the bottom 11 and plate 8, where it is not feasible to insert insulation, owing to the fact that the shell must be fitted tightly and properly in 1. Ina boiler, the combination with an upright shell having its side wall apertured,

a threaded nipple secured in each of said apertures, with their axes substantially horizontal and projecting outwardly of the shell, a boxl surrounding the projecting ends of the several nipples, cementitious insulation filling the'inner end of said box and the interstices between said nipples, and a heating element threaded into each of said nipples, and projecting within the water space of the boiler.

2. In a boiler, in combination, an upright cylindrical shell, a circular supporting table, means for securing said shell to the table, a plurality of legs supporting the table, and projecting slightly beyond the edge of the table, a cylindrical casing enclosing the shell, and resting upon the projections of said legs, and ttings extending through the side Walls of said casing and shell to retain the former in place. f

3. In a boiler, in combination, an upright shell having a box secured thereto near its bottom and projecting laterally therefrom, an enclosing casing fitting over the shell and cut away to receive said box, the portion of the casing beneath said box being flexibly connected to the remainder, to be swung back to permit passage of the box, and means securing said flexibly connected portion in the general contour of the casing, beneath the box.

4:. In a boiler, in combination, an upright shell having a box secured thereto near its bottom and projecting laterally therefrom, an enclosing casing fitting over the shell and cut away to receive said box, the portion of the casing beneath said box being flexibly connected to the remainder, to be swung back to permit passage of the box, means securing said flexibly connected portion in the general cont-our of the casing, beneath the box, a cover fitting over the upper end of said casing, a table fitting within its lower end, means securing said shell to said table, and external connections to said shell passing through the casing, cover, and table, to fix the latter relative to each other and to the shell.

5. In a boiler, the combination with a shell having its side Wall apertured near its bottom, a heating element secured in said aperture and projecting laterally within the shell, a blow-off connection to the bottom of said shell, and extending upward above the bottom thereof, adjacent but terminating below the heating element.

6. In a boiler, the combination with a shell having its side wall apertured near its bottom, a heating element received in said aperture and projecting laterally within the boiler shell, a table, means seouring'the boilershell in upright position resting upon said table, a casingspaced from the sides and top of the shell, the space between being filled with insulating material, and a blow-ofi:l oonnection-to the bottom of the shell, through said table, and extending upwardly withinV the shell to a level adjacent the heating ele- Y ment, whereby an insulating layer of scale lo is permitted to form in the bottom of the shell. v 7. In a boiler, a shell having its side wall aperturednear its bottom, a nipple received Y, in said aperture and projecting laterally 15 within the shell, a heating element received in said nipple, an insulating casing surrounding said shell, except about said aperture and heating element, a boX projecting Jfrom the shell vabout the aperture and heating' ele- "'26 ment, a removable cover closing said box to form a. dead insulatingv space therein, and a cementitious insulation lling the bottom of said box about the nipple, to induce the deposit ofk scale upon theshells bottom.

'Q23 Signed atSeattle, King County, State of Washington, this 9th day of August, 1928. Y SYDNEY N. COATES. 

